Group B streptococcal (GBS) disease is a bacterial infection.
GBS can cause illness in newborn babies, pregnant women, the elderly, and adults with other chronic medical conditions, such as diabetes or liver disease. In newborns, it is the most common cause of a blood infection called sepsis and of meningitis, which is an infection of the fluid and lining surrounding the brain.
This following information covers GBS in pregnant women and their babies.
GBS is caused by specific bacteria. These bacteria live in the gastrointestinal and genital tracts. They are found in the vaginal or rectal areas of 10% to 35% of all healthy adult women. Only a small number of babies who are exposed to the bacteria will become infected. If infection occurs, it can be serious.
Newborn babies can become infected with GBS in 3 ways:
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Factors that may increase your baby's chance of GBS include:
In pregnant women, GBS infections can sometimes cause inflammation or irritation of the lining of the uterus called endometritis, infection of the uterus and amniotic sac called amnionitis, and loss of pregnancy due to infection.
Symptoms of endometritis and amnionitis may include:
Doctors are especially concerned about how GBS infections affect young infants. The disease can occur early in newborns (early-onset) or late (late-onset). Early-onset GBS disease usually causes illness within the first 24 hours of life. However, illness can occur up to 3 days after birth. Late-onset disease usually occurs at 3 to 4 weeks of age. It can occur any time from 4 days to 3 months of age.
Symptoms of GBS include:
GBS can be diagnosed in a pregnant woman at an obstetric office visit. Testing for GBS should be done about one month before the baby is due. The doctor swabs the vagina and rectum and sends this sample to a laboratory to test for GBS. Test results are available in 24-48 hours. Treatment usually does not begin until labor starts.
Your baby's bodily fluids may be tested. This can be done with:
If you test positive for GBS or are at high risk, your doctor may recommend giving you antibiotics through an IV during labor and delivery. Antibiotics will reduce the risk that your baby will get sick after birth. Even with screening and antibiotic treatment, some babies can still get GBS.
It is generally not recommended that women take antibiotics before labor to prevent GBS unless GBS is identified in the urine. It is not as effective at preventing illness unless it is given after labor has begun.
If the doctor suspects strep B infection, a newborn might be kept in the hospital a couple of extra days for monitoring, which will include blood and urine tests. A baby diagnosed with GBS will be treated with IV antibiotics for 10 days. If GBS is suspected, antibiotics may be started before a diagnosis is made. Seek medical care right away if your baby has any of the symptoms of GBS infection.
Methods to prevent GBS may include:
Group B Strep Association
The American Congress of Obstetricians and Gynecologists
The Society of Obstetricians and Gynaecologists of Canada
Women's Health Matters
De Tejada BM, Pfister RE, Renzi G, et al. Intrapartum Group B streptococcus detection by rapid polymerase chain reaction assay for the prevention of neonatal sepsis. Clin Microbiol Infect. 2011;17(12):1786-1791.
Group B strep (GBS). Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/groupbstrep/index.html. Updated May 23, 2011. Accessed June 19, 2014.
Group B strep infection: GBS. American Pregnancy Association website. Available at: http://americanpregnancy.org/pregnancy-complications/group-b-strep-infection. Updated March 2011. Accessed June 19, 2014.
Group B streptococcal infection in infants less than 3 months old. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated May 19, 2014. Accessed June 19, 2014.
Ohlsson A, Shah VS. Intrapartum antibiotics for known maternal Group B streptococcal colonization. Cochrane Database Syst Rev. 2009;(3):CD007467.
Puopolo KM, Madoff LC, Eichenwald EC. Early-onset Group B streptococcal disease in the era of maternal screening. Pediatrics. 2005;115(5):1240-1246.
Woodgate P, Flenady V, Steer P. Intramuscular penicillin for the prevention of early onset Group B streptococcal infection in newborn infants. Cochrane Database Syst Rev. 2004;(3):CD003667.
Last reviewed June 2016 by Michael Woods, MD Last Updated: 6/19/2014